Fix git push in publish workflow

[bquorning]

The final git push is failing because of our branch protection rules: https://github.com/rubocop/rubocop-rspec/actions/runs/8561970997/job/23464311900

@ydah suggested maybe the solution is as follows:

• creating a service account user that has read-write access to repo
• create a pat for that service account
• add the service account to the bypass protection rules in the branch
• create a repo secret that contains the PAT token
• push using the created service account

[bquorning]

Fixed by #1869.